Famous for his performing and writing work on the Toronto-based sketch comedy show SCTV (Second City Television), he is also known for his series regular role as Harold Weir on the NBC program Freaks and Geeks.
In the early 1970s, while working with the Chicago branch of the Second City comedy troupe, he was featured on the National Lampoon Radio Hour.
He guest-starred in episodes of Family Guy and The Big Bang Theory as characters who were variations on his memorable Western Union deliveryman role from Back to the Future Part II.
The brother of fellow comedy writers Paul and David Flaherty, he spent his early years in Pittsburgh, Pennsylvania and Chicago, Illinois, and later lived in Toronto, Ontario and Los Angeles, California. He has two children: a daughter named Gudrun and a son named Gabriel.
He and comedian John Candy both rose to fame on SCTV.